The call rate to New Zealand’s national Quitline service¹ appears to be influenced by mass media campaigns,² media publicity on the risks of smoking,³ and even international events.⁴ We examined the usage of this Quitline before and after the time that new smoke-free environments legislation became operational in New Zealand on 10 December 2004. This legislation extended previous legislation so as to completely ban smoking in bars, restaurants, and nearly all indoor workplaces. It appears that this new law has been well accepted by smokers.⁵

We analysed routinely collected data on smokers who registered with the Quitline to undertake a quit attempt, comparing the period from 1 December 2004 to 31 January 2005 (the “intervention period”) with the same period 12 months previously (the “pre-intervention period”). The same particular months were selected since caller registration rates vary widely throughout the year by season. The Factiva electronic database for newspaper articles was also searched for articles in the “New Zealand major papers” section of the database that mentioned “smoking” or “smokefree” (during the two periods).

In the “pre-intervention period” the caller registration rate was 272 per 100 000 smokers (aged 15+ years) per month, compared to 395 per 100 000 per month in the “intervention period” (rate ratio (RR) 1.44, 95% confidence interval (CI) 1.39 to 1.51). Similarly, the rate of distribution of first time voucher cards for subsidised nicotine replacement therapy via the Quitline also increased (RR 1.92, 95% CI 1.82 to 2.03). There was an increase in the proportion of registrations in the 35–44 year age group (p  =  0.01), but no other significant changes in the distribution of callers by sex or ethnic group (table 1).

Weekly caller registration rates also increased in the “intervention week” (that is, when the law became operational) relative to the average for the three weeks preceding this week (944 v 558 callers, respectively) (RR 1.69, 95% CI 1.52 to 1.88). This increase persisted into the following week, even though it was the week preceding Christmas day (RR 1.27, 95% CI 1.14 to 1.42).

In the “pre-intervention period” the Factiva database recorded 271 newspaper articles with the words “smoking” or “smokefree”, compared to 376 in the “intervention period”. In contrast, television advertising expenditure promoting the Quitline number was lower in the intervention period but there was some paid advertising to inform the public of the new legislation. Indeed, the proportion of first time callers who reported television advertising as the source of information about the Quitline declined in the intervention period (p  =  0.03) (table 1). There was also a significant decline in the proportions of the “friends and family” and “health worker” sources of information (p < 0.0001 for both).

Given these patterns, it would seem that Quitline advertising patterns or changes in health worker support are unlikely to explain the increased caller registration rate in the intervention period. Instead, the increased use of the Quitline is probably attributable to the media publicity and discussions around the new smoke-free legislation, and the experience of the smoke-free workplaces. Therefore, in addition to smoke-free laws protecting non-smokers, this study supports the findings from elsewhere,^6–9 that such laws can promote quitting attempts by smokers.